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Two lamps are rated 40W and 220V each are connected in series. The total power d...



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  • the correct answer is 20W.USING P=I^2*R
    making R subject of formula
    R=I^2/P =
    (220)^2/40=1210
    now 1210 multiplied by the two lamps=1210*2=2420
    THEN P=V^2*R =(220)^2/2420=20W JUST TRY IT

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  • Charity Ali

    The answer is 20w,
    Using R=V²/P
    R=(220)²/40= 48400/40=1210
    For the two lamp,
    R= 1210×2 = 2420
    P=V²/R
    P= (220)²/2420
    P=20w